C=-10x^2-2500x+1000000

Solution for C=-10x^2-2500x+1000000 equation:

=-10C^2-2500C+1000000

We move all terms to the left:

-(-10C^2-2500C+1000000)=0

We get rid of parentheses

10C^2+2500C-1000000=0

a = 10; b = 2500; c = -1000000;
Δ = b2-4ac
Δ = 25002-4·10·(-1000000)
Δ = 46250000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$C_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$C_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{46250000}=\sqrt{250000*185}=\sqrt{250000}*\sqrt{185}=500\sqrt{185}$
$C_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2500)-500\sqrt{185}}{2*10}=\frac{-2500-500\sqrt{185}}{20}
$
$C_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2500)+500\sqrt{185}}{2*10}=\frac{-2500+500\sqrt{185}}{20}
$